Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems, IEEE 802.11 carrier sense multiple access/collision avoidance (CSMA/CA) and Bluetooth frequency hopping spread spectrum (FHSS) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-input-single-output, multiple-input-single-output or a multiple-input-multiple-output (MIMO) system.
The Institute of Electrical and Electronic Engineers (IEEE) 802.11 working group has been developing an amendment for a high-throughput physical layer (PHY), called 802.11n. The IEEE 802.11n standard includes two bandwidths, an original 20 MHz and a new optional 40 MHz. There have been numerous concerns about the effect of the 40 MHz version of the IEEE 802.11n on other wireless networks, such as Bluetooth operating in the 2.4 GHz frequency band.